"Dual" typically indicates multiple audio tracks, most commonly Hindi + English for this specific uploader.
: The file contains Dual Audio tracks, usually Hindi and English, or Hindi and the original language. 720p : The resolution is High Definition (HD), MS EP4 Dual 720p HEVC - Vegamovies.NL.mkv
This is a popular third-party site known for providing highly compressed versions of mainstream web series. "Dual" typically indicates multiple audio tracks